272 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



fig. 7 is somewhat restored. It is, upon the specimen, split in two along the 

 midrib, and the nervation, as well as that of fig. 9, is mostly obsolete; the 

 point of the veins being so indistinct that it is not possible to see if they 

 curve under the teeth or enter them. The nervation of fig. 8 is more distinct, 

 and of the same character as that of fig. 6 of the former species. The shape 

 of the fragmentary leaf of fig. 9, and its border divisions, are comparable to 

 those of Quercus lUcoides, Heer (Fl. Tert. Helv , iii, p 180, pi. cli, fig. 26); 

 by the flat, apparently cartilaginous, border; it is also related to /. dryan- 

 drcefoUa, Sap. (Et., 1, 2, p. 89, pi. 10, fig. 8), which, like this species, has 

 smaller, narrower, linear leaves, either with shorter teeth or with large ones, 

 deeply cut, in long spiniform divisions. The nervation is, however, different. 

 Habitat. — Sage Creek, Montana, with Sequoia Ileerii; this one repre- 

 sented in numerous fragments (Dr. F. V. Hayden). 



KHAMNE^. 



This family of plants does not occupy an important place in the present 

 North American flora. It is there represented by a few species of shrubs of 

 the genera Pallurus, Zizyplius, Berchemia, Rhamnus, Ceanothus ; the three 

 first of which by one species each, Rhamnus by three in the Atlantic and 

 as many in the Pacific slope, and Ceanothus by four Eastern and eighteen 

 Californian species. Two other genera, Colubrina and Gouania, have each 

 one species in Florida. In the geological times, the species of this group 

 appear in comparatively larger numbers, except, however, in Ceanothus; for 

 European authors have described nine Miocene species of Paliurus, eight- 

 een o^ Zizyphus of the same period, with three Eocene species. Berchemia 

 has three, Rhamnus thirty-four, Miocene, mostly in the lower divisions of 

 the formation, with one Eocene, and Ceanothus only one. As this family at 

 the present epoch is generally distributed, in tropical regions, Zizyphus in 

 Asia and Africa, Rhamnus in South America, the numerous species of the 

 Miocene serve as records of the climate. From the Eocene of Mississippi, 

 one species of Ceanothus and one of Rhamnus have been published (Trans. 

 Amer. Philos. Soc, vol. xiii, pp. 419, 420); the Cretaceous flora of the Dakota 

 group has one leaf referred 1o Paliurus. Those described here seem to 

 indicate in our Tertiary a distribution corresponding to that of the Rhamnece 

 in the European Miocene. Besides these, one Zizyphus and one Ceanothus 

 are recognized in the Pliocene flora of California. 



